Assessment of hemostatic changes after crystalloid and colloid fluid preloading in trauma patients using standard coagulation parameters and thromboelastography

BACKGROUND: The choice of an ideal fluid administered post trauma and its subsequent influence on coagulation still poses a clinical dilemma. Hence, this study was designed to assess the influence of in vivo hemodilution with various fluid preparations (4% gelatin, 6% hydoxyethyl starch (HES), Ringer's lactate, 0.9% normal saline) on coagulation using standard coagulation parameters and real-time thromboelastography (TEG) in patients undergoing elective surgery post trauma. METHODS: In a randomized, double-blind study, 100 patients of either sex and age, belonging to ASA Grades I and II, scheduled for elective surgeries were allocated into four groups of 25 each according to the type of fluid infused. Group G (4% gelatin), Group N (0.9% normal saline), Group R (Ringer's lactate), and Group H (6% HES) received preloading with 1 L of fluid according to the group. The coagulation status of the patients was assessed during perioperative period (before surgery, after fluid preloading, and at the end of the surgery) using both conventional coagulation analysis and TEG. STATISTICAL ANALYSIS: Analysis of variance (ANOVA), post hoc and Pearson Chi-square test were used. RESULTS: In all the patients preloaded with gelatin, there was a significant increase in prothrombin time index (PTI; 14.88±0.90 vs. 13.78±3.01, P<0.001) and international normalized ratio (INR; 1.12±0.09 vs. 1.09±0.19, P<0.05) compared to the baseline value. An increase was observed in these parameters in the postoperative period also. In the HES group, there was statistically significant increase in PT time (15.70±1.51 vs. 13.74±0.75, P=0.01) and INR (1.20±0.15 vs. 1.03±0.17, P<0.001) as compared to the baseline. In the intergroup comparisons, the patients preloaded with HES had a significant increase in INR (1.20±0.15 vs. 1.12±0.09, P=0.04) and reaction time (R time; 6.84±2.55 min vs. 4.79±1.77 min, P=0.02) as compared to the gelatin group. The fall in coagulation time (k time; 2.16±0.98 vs. 3.94±2.6, P=0.02), rise in maximum amplitude (MA; 61.94±14.08 vs. 50.11±14.10, P=0.04), and rise in A20 (56.17±14.66 vs. 43.11±14.24, P=0.05) were more in patients preloaded with RL as compared to the HES group. 100% patients in the gelatin group, 84.2% patients in the NS group, 94.4% patients in the RL group, and 66.7% patients in the HES group had hypocoagulable (R time > 14 min) state in the postoperative period. CONCLUSION: Crystalloids are optimal volume expanders in trauma, with RL having beneficial effects on coagulation system (decrease in k time and increase in MA and A20). Among the colloids, HES 6% (130/0.4) affects coagulation parameters (increase in PTI, INR, R time, k time) more than gelatin. Trial registration (protocol number-IEC/NP-189/2011).